DE102019100798A1 - Method and system for active steering in start-stop events - Google Patents

Abstract

A vehicle will be provided. The vehicle may include a motor configured to automatically stop and automatically start. The system may further include a controller programmed to drive an electric actuator coupled to a steering mechanism to synchronize a drive angle of the vehicle and a steering wheel angle of the vehicle in response to a parameter indicative of a Probability of a wheel slip event exceeds a threshold and that the steering wheel angle is greater than a predetermined threshold.

Description

TECHNICAL AREA

This disclosure relates to a vehicle system for steering a vehicle during a start-stop event and a method of operating the same.

GENERAL PRIOR ART

The fuel efficiency and emission behavior of an automobile is a property of great importance. Greater fuel efficiency and lower emissions ratings can make a vehicle more appealing to potential buyers and help an automaker comply with fuel efficiency and emissions standards imposed by state governments. For conventional gasoline or diesel vehicles, a method for reducing fuel consumption is the use of a micro-hybrid or start-stop powertrain system that selectively shuts down its engine during portions of a drive cycle (auto-stop event).

Some vehicles include an active front steering (AFS) system to improve steering performance. The AFS system may be electro-mechanical and include an electronically-controlled engine and transmission superimposed on an additional steering angle based primarily on vehicle speed and steering wheel angle. Under certain conditions, such as an auto-stop event, the AFS engine is stopped or stopped so that movement of the steering wheel does not change the position of the wheels. When the AFS engine is stopped, the AFS engine will maintain its current position regardless of any additional movement of the steering wheel. Since the AFS motor holds the angle of the vehicle wheels, movement of the steering wheel may cause a misalignment or error between the steering wheel and the vehicle wheels.

SUMMARY

In accordance with one embodiment of this disclosure, a method of controlling an active steering system is provided. The method may include driving an electric actuator coupled to a steering mechanism to synchronize a drive angle of the vehicle and a steering wheel angle of the vehicle by a controller in response to a parameter indicating that a wheel slip event is a threshold exceeds and that the steering wheel angle is greater than a predetermined threshold.

In accordance with another embodiment of this disclosure, a vehicle system is provided. The system may include a motor configured to automatically stop and automatically start. The system may further include a controller configured to initiate an autostart of the engine in response to a difference between a steering wheel angle and a drive angle being greater than a predetermined threshold.

In accordance with yet another embodiment of this disclosure, a vehicle is provided. The vehicle may include a motor configured to automatically stop and automatically start. The system may further include a controller programmed to drive an electric actuator coupled to a steering mechanism to synchronize a drive angle of the vehicle and a steering wheel angle of the vehicle in response to a parameter indicative that Wheel slip event exceeds a threshold and that the steering wheel angle is greater than a predetermined threshold.

list of figures

• 1 FIG. 12 is a schematic of an exemplary steering system incorporating active front wheel steering. FIG.
• 2 Figure 12 is a schematic of an example stop / start vehicle illustrating typical components.
• 3 FIG. 10 is an operational flowchart of the stop / start vehicle and the associated steering system according to a first embodiment of this disclosure. FIG.
• 4 FIG. 10 is an operational flowchart of the stop / start vehicle and the associated steering system according to a second embodiment of this disclosure. FIG.

DETAILED DESCRIPTION

Detailed embodiments of the present invention are disclosed herein as needed; however, it should be understood that the disclosed embodiments of the invention, which may be embodied in various and alternative forms, are merely exemplary. The figures are not necessarily to scale; some features can be zoomed in or out to show details of specific components. Thus, specific structural and functional details disclosed herein are not to be construed as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

Under certain circumstances, an angle of a steering wheel and an angle of the vehicle wheels (eg, a drive angle) may not match. Synchronizing the drive angle and the steering wheel angle may be difficult under low traction conditions. To correct for this fault condition, a controller may drive an electric actuator coupled to a steering mechanism to synchronize a drive angle of the vehicle and a steering wheel angle of the vehicle.

An object of controlling a start-stop vehicle powertrain may include stopping an engine, such as an internal combustion engine (eg, a gasoline engine or a diesel engine). The controller may be used to stop the engine by preventing an ignition coil of the engine or by preventing the injection of fuel into cylinders of the engine. The controller may stop the engine based on inputs from vehicle sensors. The signals from the sensors may indicate a speed of the vehicle, a force applied to the brake pedal (or absence thereof), a force applied to the accelerator pedal (or absence thereof), a pitch angle of the vehicle, the weight of the vehicle, or other vehicle characteristics. A rolling start-stop system (RSS) is an extension of a conventional start-stop system.

A conventional start-stop system may be configured to automatically stop the engine when the vehicle is not moving (eg, 0 mph), a force is applied to the brake pedal, and the voltage level of the vehicle battery is above a threshold , The threshold is selected based on the energy needed to start the engine with an electric starter. Once the engine is stopped, the controller may automatically start the engine if the selector lever is set to drive and there is an absence of force applied to the brake pedal. In other embodiments of a start-stop vehicle, the controller may be configured to automatically stop the engine when the vehicle is moving at a speed below a lower speed threshold (eg, 2 mph or 4 mph), a force on the engine Brake pedal is applied and the voltage level of the vehicle battery is above a threshold. Along with the conventional start-stop control system, a vehicle may be configured to control the engine via start-stop when the vehicle is in motion above a lower threshold. This system is also called Rolling Start-Stop System (RSS).

An RSS can provide additional benefits such as improved fuel efficiency rating, improved vehicle emissions, and reduced engine noise. These advantages can be added to the improvements of a conventional start-stop system. An RSS allows the engine to automatically stop at a higher vehicle speed as soon as the driver applies the brakes, the vehicle speed is below an upper vehicle speed threshold, a transmission torque converter clutch is open, and the transmission is in the appropriate gear.

Generating power from the engine only when needed / needed is one of the main approaches to maximizing fuel efficiency while minimizing emissions in vehicles equipped with internal combustion engines. Accordingly, RSS systems are being considered for implementation across a range of modern vehicles for all key markets around the world. An RSS system may include a battery system that may have implemented a single battery, two batteries, or any number of batteries. The battery system may have an operating voltage that is approximately equal to a standard vehicle battery (i.e., 12 volts) or operated at other voltages (eg, 24V, 48V). RSS systems may use any combination of the same or different technologies of batteries or power sources, such as lead acid, enhanced flooded (EFB), absorbent glass mat (AGM), Li-ion, or any other battery technology.

One of the challenges in implementing RSS technology in vehicles is steering the vehicle's steering system during low power situations (auto-stop event). When the vehicle is stopped, there may not be enough energy to drive the AFS motor to adjust the drive angle of the vehicle wheels to correspond to the angle of the steering wheel. The challenge can be even more complicated if the vehicle is driven on a low friction surface, e.g. As snow, rain or ice, is operated. Sensors configured to detect such conditions may communicate with a controller to modify the AFS and RSS systems.

With reference to 1 is an illustration of an exemplary steering system 28 for a vehicle 10 illustrated. The steering system 28 can be a module 20 for Active Front Steering (AFS). The AFS module 20 can driving the steering mechanism 24 support a translation ratio with that the wheels rotate in response to a rotation of a steering wheel to vary. For example, at low vehicle speeds, a low gear ratio can be implemented such that the steering wheel for a certain steering angle must be taken less. This allows sharp turns to be made with less steering wheel input. At higher vehicle speeds, the gear ratio can be increased so that the steering wheel is taken for a certain steering angle more. This reduces the vulnerability of the steering system 28 for changes to the steering wheel at higher speeds. The net result is that the wheels turn less at higher speeds in response to turning the steering wheel.

The steering system 28 may include an Electric Power Assisted Steering (EPAS) module 22 connected to the steering mechanism 24 can work together. The EPAS module 22 can driving the steering mechanism 24 assist to reduce the amount of operator effort required to steer the vehicle 10 is needed. The EPAS module 22 may include an electric motor when driving the steering mechanism 24 helps. The EPAS module 22 may supplement torque in addition to the torque provided by the operator to change the direction of the front wheels.

The steering system 28 can be a steering wheel 50 which is operated by the operator. The steering system 28 can the movement of the steering wheel 50 in a shift of the front wheels 52 convert to a change of direction of the vehicle 10 to induce. In the steering mechanism 24 it can be a rack configuration 60 and gear 62 act, with the front wheels 52 with the rack 60 are coupled and the steering wheel 50 with the gear 62 is coupled.

The AFS module 20 can be an electric actuator or an electric machine 56 include, the or with a spur gear or a planetary gear set 58 is coupled. The electric machine 56 can the gear 62 cause to turn what the rack 60 can cause it to move, and the front wheels 52 can cause it to change direction. The steering wheel 50 can also by the AFS wheelset 58 be coupled. A variable gear ratio between the steering wheel 50 and the wheels 52 can by running the AFS module 20 for driving the gear 62 be initiated when the steering wheel 50 is taken. The gear ratio may be a ratio between the steering wheel angle and an angle at which the wheels are wrapped (eg, a drive angle). A controller 54 may be a steering wheel angle input signal 64 receive that on a position of the steering wheel 50 indicates and can one or more output signals 66 generate to the electric machine 56 to operate. Additional inputs and outputs may be through the controller 54 be used. The control 54 may communicate with other controllers, such as an engine controller or vehicle system controller.

The control 54 may be programmed to the steering wheel angle input signal 64 from the steering wheel 50 to monitor. The control 54 can also be programmed to monitor the drive angle. For purposes of this disclosure, "drive angle" means the current position of the wheels 52 , The control 54 can determine a position difference between the steering wheel angle and the drive angle (eg AFS error). Based on the AFS error, the controller can 54 a demand current for the electric machine 56 determine. The control 54 Can the electricity through the electric machine 56 via the output signals 66 control.

The AFS module 20 can be a locking mechanism 68 include. In the locking mechanism 68 it may be a solenoid operated device that, when actuated, the electric machine 56 prevents the gear 62 to turn. When the locking mechanism 68 can be engaged, the AFS module 20 does not assist in steering the vehicle and steering is done using an output of the steering wheel 50 reached. The locking mechanism 68 can by an output signal 70 from the controller 54 being controlled.

The modules for EPAS 22 and AFS 20 are with a power network 18 coupled and conduct electrical power from the electric machine 14 or the battery 119 from. In operation, the modules for EPAS 22 and AFS 20 a significant amount of power from the power grid 18 Respectively. Under conditions in which the engine 102 runs and the electric machine 14 electrical power to the power grid 18 can deliver that in the battery 119 stored energy can not be used up. If the engine 102 However, not running, the electrical power is through the battery 119 provided. The result can be a voltage drop in the power network 18 be, which adversely affects the modules for EPAS 22 or AFS 20 can affect. For example, the voltage can drop far enough that the modules for EPAS 22 or AFS 20 can not work properly anymore.

With reference to 2 includes a micro hybrid vehicle 10 (also known as start-stop vehicle) an engine 102 and a gearbox 104 , A crankshaft of the engine 102 is in drive connection with the transmission input shaft 106 to transfer power from the engine to the transmission. The gear 104 includes an output shaft 108 that is drivingly connected to a differential 110 stands. The differential 110 provides for the driven wheels 114A and 114B over one or more axes - such as half-waves 112A and 112B - selectively power ready. In some embodiments, the differential is 110 arranged within the gear housing. The vehicle 10 also includes a motor starter 116 Configured to turn the crankshaft to the engine 102 in response to a motor start signal from the controller 54 to turn. At the engine starter 116 it may be an extended starter designed specifically for the increased load cycle associated with a micro hybrid vehicle. The ignition 116 is from a battery 119 powered, which may be a 12 volt battery, a 24 volt battery, a 48 volt battery, or other low voltage battery or high voltage battery.

A low voltage battery is a battery with a DC voltage below 100 volts, a high voltage battery is a battery with a DC voltage equal to or greater than 100 volts. In some embodiments, the engine may include multiple starters. A first starter may engage a ring gear of the flywheel to rotate the engine. A second engine may be connected to the crankshaft pulley by belt, chain or other means known in the art. Particularly in the case of RSS, the vehicle may have a dual battery system, i. H. a 12 volt battery to start and a 12 volt battery to support the electrical loads when the engine is off and the vehicle is moving. The two batteries are typically isolated by a circuit breaker.

An accelerator pedal 122 provides operator inputs for controlling a speed of the vehicle 10 ready. The pedal 122 may include a pedal position sensor that provides a pedal position signal for control 54 provides the control signals for the engine 102 provides.

A brake pedal 124 provides operator inputs for controlling the brakes of the vehicle. The brake control 126 receives operator input through a brake pedal 124 and controls a friction braking system that controls the wheel brakes 130A and 130B and which can be operated to apply a braking force to the vehicle wheels, such as vehicle wheel 114A and vehicle wheel 114B to apply. The pedal 124 may include a pedal position sensor that provides a pedal position signal for control 54 provides. The vehicle may include an electric parking brake that is in communication with the controller 54 stands. The control 54 is programmed to automatically engage the parking brake if desired.

In another embodiment, the vehicle may be equipped with a manual transmission and an associated clutch pedal (not illustrated). Like the pedal mentioned above 124 The clutch pedal may be equipped with a pedal sensor that provides a pedal position signal for the control 54 provides.

In the control 54 It can be a variety of controllers that can communicate over a serial bus (eg Controller Area Network (CAN), FlexRay, Ethernet, etc.) or via dedicated electrical lines. The controller generally includes any number of microprocessors, microcontrollers, ASICs, ICs, volatile (eg, RAM, DRAM, SRAM, etc.) and nonvolatile memory (eg, FLASH, ROM, EPROM, EEPROM, MRAM, etc .) and software code to interact to perform a series of operations. The controller may also include predetermined data or "look-up tables" based on calculations and test data stored in the memory. The controller may communicate with other vehicle systems and controls via one or more wired or wireless vehicle connections using common bus protocols (eg, CAN, LIN, Ethernet, etc.). As used herein, a reference to "one controller" refers to one or more controllers.

As noted above, embodiments of the present invention include a control system for controlling a start-stop system for an engine in a vehicle, such as the engine 102 and the vehicle 10 , Such a control system may be embodied by one or more controllers, such as the controller 54 , One goal of a vehicle start-stop system is to automatically stop the engine under certain conditions while automatically restarting it when conditions change. This provides greater fuel efficiency and reduced emissions.

In some start-stop systems, the engine may be automatically stopped ("automatically stopped") if all or a certain set of conditions are met. For example, if the selector lever is DRIVE, the brake pedal is depressed, the accelerator pedal is released, and the vehicle speed is zero, the engine may stop 102 be stopped automatically. Another condition that may be included in this conditional clause is that none of the vehicle subsystems (eg, air conditioning or power steering) requires the engine to be running. In a start-stop system where all conditions must be met before the engine is automatically stopped, the start-stop system not only prevents the engine from being automatically stopped if any of the conditions in the set are not met but once the engine is automatically stopped, the engine can be restarted automatically if any of the conditions change.

Continuing the above example, one of the usual conditions for stopping an engine is that a vehicle speed or vehicle speed is zero. Often, an engine is not stopped while the vehicle is moving. In some systems, the vehicle speed may be greater than zero but less than a lower speed threshold, such as 1.5 mph or 3.5 mph. Here, a rolling start-stop system allows the engine 102 to be stopped automatically if the vehicle speed is within a speed range.

Another vehicle characteristic that must be considered in calculating an engine shut-off point is a capacity and pressure of a vacuum tank used to provide brake booster vacuum assistance. The upper threshold speed may be selected from a speed range, such as 15 mph to 60 mph. The ability of the vehicle to steer and stop depends on many conditions of the vehicle, including speed, weight, angle of inclination, braking conditions, road conditions and tire conditions. As these conditions change, so does the vehicle's ability to steer and stop. For example, it is more difficult to stop a vehicle going downhill than if the vehicle were going uphill. Therefore, a controller 54 be configured to set a fixed lower threshold based on a lower speed to protect against a number of conditions that affect the stopping of the vehicle. The control 54 may also be configured to set a fixed upper threshold based on an upper speed to protect against a number of conditions that affect stopping the vehicle. Alternatively, the controller 54 configured to dynamically change the lower threshold and upper threshold based on the vehicle conditions at a time.

The vehicle 10 may be equipped to detect or determine the presence of a low friction road surface. The presence of a low friction road surface can cause the wheels 52 slip or idle, thus preventing the vehicle from reaching the required speed. In particular, the vehicle can 10 a temperature sensor 138 include that with the vehicle sensors 128 and the controller 54 communicated. If that the vehicle 10 surrounding ambient temperature is below a threshold (eg, 32 degrees Fahrenheit), the controller may 54 determine the likelihood of a tire slip event. The vehicle can also have a rain sensor 140 include that with the vehicle sensors 128 and the controller 54 communicated. If rain or other precipitation (eg snow, sleet or ice) is detected, the controller may 54 determine the likelihood of a tire slip event. The vehicle may also include a traction control module 142 include. The traction control module 142 may include an antilock system capable of detecting slippage or tire slippage. In addition, the traction control module 142 Wheel speed sensors include the rotational speed of the wheels 52 and 114 measure up. The traction control module 142 or the controller 54 or both can be a difference in the rotational speed between the tires 52 and 114 to capture. If one or more of the wheels, z. B. 52a to turn faster than the other wheels, z. B. 52b . 114a or 114b , a slip condition can be detected.

The control 54 may also be configured to change the vehicle speed threshold based on the conditions of the vehicle at a future time. For example, a navigation system or a human-machine interface (HMI), which is a navigation system 132 includes, so with the controller 54 coupled, that a distance for the control can be provided. The route may include a height change along the route and adjust the upper and lower speed thresholds according to changes in possible braking along the route. The route may also include changes in posted speeds that indicate locations where the brakes can be applied to reduce the speed, or an accelerator pedal can be used to increase the speed. The route may include places that are potential stopping points, such as fixed locations and dynamic locations. A fixed location where a possible stop point is located includes a traffic light, a stop sign, a roundabout, or a drive-by sign. A dynamic location where there is a potential stop point on the route includes places associated with traffic jams, weather conditions, road construction or accidents. The route taken by the navigation system within the HMI 132 is displayed, can be based on map data, in advance in the memory of the HMI 132 were loaded, or the HMI 132 can receive data streamed from a remote server. The data may be wirelessly streamed using cellular, wireless or other standard technology. Based on the distance, altitude changes and possible stopping points along the route, the controller can 54 the voltage level of the starter battery 118 set to a state of charge of the starter battery 118 maintain. The setting restricts power to electrical accessories through the battery 118 including electric power steering (EPS), electric power brakes, electric stability control (ESC) and other vehicle dynamics systems.

Now referring to 3 FIG. 3 is a flowchart illustrating an operation of a system or method 300 of the active front wheel steering system 28 and the start-stop system of the vehicle 10 illustrated. As described above, various illustrated functions or processes may be performed in a different order, may be omitted, or may be performed repeatedly, although not explicitly illustrated or described, to achieve the various features and advantages described herein, as one of ordinary skill in the art can understand.

Controlling or operating the active front wheel steering system 28 and the start-stop system of the vehicle 10 can at process 302 start. While the speed of the vehicle is decreasing below a threshold V, as by operation 304 shown, the controller can 54 the vehicle 10 stop automatically, as by operation 306 shown. The control 54 may receive a signal indicative of a resumption of driving, as by operation 308 shown. The signal can be triggered by a user or driver who is on the gas pedal 122 or sets the selector lever to drive, and if there is an absence of force applied to the brake pedal.

As previously mentioned, the controller monitors 54 the AFS error and the angle difference between the drive angle (eg the current wheel position) and the steering wheel angle (as positioned by the driver or operator). The AFS error can change (increase or decrease) under certain circumstances. A relatively small AFS error ( 0 , 1 degree to 5 degrees) may be present if the steering mechanism 24 not with the steering wheel 50 is aligned. This may be due to a misalignment procedure or after one of the wheels 52 hit a pothole or a curb. The AFS error may increase after the steering wheel 50 and the wheels 52 were smashed before the vehicle 10 was automatically stopped and after the steering wheel 50 was hit in the opposite direction. Alternatively, the AFS error can be corrected by adjusting the steering wheel 50 caused or increased during an auto-stop event. Or the AFS error may be due to the onset of a safety lock while the steering wheel 50 is taken, caused or increased. If the change in the AFS error exceeds a threshold x as determined by act 310 shown, the controller jumps 54 to process 312 ,

If the error is the threshold x exceeds the AFS system sends 28 a signal to the controller 54 to the engine 102 to start automatically, as by operation 312 shown. The powertrain or the engine 102 Restarts as by operation 314 shown, and the vehicle starts automatically, as by operation 316 shown. Once the vehicle 10 automatically starts, will provide sufficient power for the electric AFS actuator or AFS engine 56 provided as by operation 318 shown. Once sufficient power for the engine 56 is provided, the AFS error can be lowered by synchronizing the drive angle with the steering wheel angle. Synchronizing the drive angle and the steering wheel angle can be done step by step (eg 3-20 minutes).

Now referring to 4 Figure 3 is a flow chart illustrating the operation of a system or method 400 of the active front wheel steering system 28 and the start-stop system of the vehicle 10 illustrated according to a second embodiment. As described above, various illustrated functions or processes may be performed in a different order, may be omitted, or may be performed repeatedly, although not explicitly illustrated or described, to achieve the various features and advantages described herein, as one of ordinary skill in the art can understand.

Controlling or operating the active front wheel steering system 28 and the start-stop system of the vehicle 10 can at process 302 start. While the speed of the vehicle is decreasing below a threshold V, as by operation 304 shown, the controller can 54 the vehicle 10 stop automatically, as by operation 306 shown. The control 54 may receive a signal indicative of a resumption of driving, as by operation 308 shown. The signal may be by a user or driver be triggered, on the gas pedal 122 or sets the selector lever to drive, and if there is an absence of force applied to the brake pedal.

The control 54 , the traction control module 142 or a combination thereof, the likelihood of a tire slip condition, as by operation 400 represented, determine. As previously mentioned, the likelihood of a tire slip condition may be a function of the temperature outside the vehicle, such as the temperature sensor 138 is measured. The likelihood of a tire slip condition may depend on the presence of precipitate, such as that caused by the rain sensor 140 is measured. In addition, the traction control module 142 detect or predict a tire slip condition. If the probability of a tire slip condition exceeds a predetermined threshold Y, control jumps to action 402 ,

In another embodiment, the vehicle may be equipped with imaging devices (eg, cameras) to detect the presence of rainfall on a roadway.

The control 54 may also determine the steering wheel angle, and whether the steering wheel angle exceeds a threshold α, as by operation 402 shown. If the steering wheel angle exceeds a threshold α, control jumps to action 318 , The control 54 can then provide sufficient power for the AFS engine 56 deploy as by operation 318 shown. Once the AFS engine 56 driven, the AFS engine can 56 then operated to synchronize the drive angle with the steering wheel angle, as by operation 320 shown. Referring again to the process 402 the controller jumps to operation 404 if the steering wheel angle is less than the threshold α. At process 404 then the controller allows a subsequent auto-stop event.

Although exemplary embodiments are described above, these embodiments are not intended to describe all possible forms of the invention. Rather, the terms used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. In addition, the features of various implementing embodiments may be combined to form further embodiments of the invention.

According to the present invention, a method for controlling an active steering system for a vehicle includes driving an electric actuator coupled to a steering mechanism to synchronize a drive angle of the vehicle and a steering wheel angle of the vehicle by a controller in response to a parameter, indicating that a probability of a wheel slip event exceeds a threshold and that the steering wheel angle is greater than a predetermined threshold.

In one embodiment, the parameter is based on detection of precipitation by a precipitation sensor.

According to one embodiment, the parameter is based on a rotational speed difference between a first wheel and a second wheel.

In one embodiment, the parameter is based on an outside temperature being less than a predetermined temperature threshold.

In one embodiment, the above invention is further characterized by initiating a startup after drive.

According to the present invention, there is provided a vehicle system comprising: a motor configured to automatically stop and automatically start; and a controller programmed to initiate an autostart of the engine in response to a difference between a steering wheel angle and a drive angle being greater than a first predetermined threshold.

In one embodiment, the controller is further programmed to drive an electrical actuator to decrease the difference to a second predetermined threshold that is less than the first predetermined threshold in response to the engine starting up.

In one embodiment, the controller is further programmed to initiate auto-start of the engine in response to an increase in angular error - a difference between the steering wheel angle and the drive angle before an auto-stop and the steering wheel angle and drive angle after an engine stop Exceed angle error threshold.

In one embodiment, the controller is further programmed to drive the electrical actuator to decrease the angle error.

In one embodiment, the controller is further programmed to command the electrical actuator to adjust an angular position of one or more wheels.

In one embodiment, the controller is further programmed to command the electrical actuator to adjust an angular position of a steering wheel mechanism.

According to the present invention, there is provided a vehicle comprising: a motor configured to automatically stop and automatically start; and a controller programmed to drive an electric actuator coupled to a steering mechanism to synchronize a drive angle of the vehicle and a steering wheel angle of the vehicle in response to a parameter indicating that a likelihood of wheel slip is present. Event exceeds a threshold and that the steering wheel angle is greater than a predetermined threshold.

In one embodiment, the controller is further programmed to drive the electrical actuator in response to the temperature measured outside the vehicle being less than a temperature threshold.

In one embodiment, the controller is further programmed to drive the electrical actuator in response to a precipitation sensor sending a signal indicative of the presence of precipitation.

In one embodiment, the controller is further programmed to drive the electrical actuator in response to a wheel speed difference between at least two of the wheels exceeding a wheel speed error threshold.

In one embodiment, the predetermined threshold is forty-five degrees.

In one embodiment, the controller is further configured to automatically stop the engine in response to the steering wheel angle being less than a predetermined threshold.

In one embodiment, the predetermined threshold is forty-five degrees.

Claims (15)

A method of controlling an active steering system for a vehicle, comprising: Driving an electric actuator coupled to a steering mechanism to synchronize a drive angle of the vehicle and a steering wheel angle of the vehicle by a controller in response to a parameter indicating that a likelihood of a wheel slip event exceeds a threshold and the steering wheel angle is greater than a predetermined threshold. Method according to Claim 1 wherein the parameter is based on detection of precipitation by a precipitation sensor. Method according to Claim 1 wherein the parameter is based on a rotational speed difference between a first wheel and a second wheel. Method according to Claim 1 wherein the parameter is based on an outside temperature being less than a predetermined temperature threshold. Method according to Claim 1 further comprising initiating an autostart after driving. A vehicle system comprising: a motor configured to automatically stop and start automatically; and a controller programmed to initiate an autostart of the engine in response to a difference between a steering wheel angle and a drive angle being greater than a first predetermined threshold. Vehicle system after Claim 6 wherein the controller is further programmed to drive an electrical actuator to decrease the difference to a second predetermined threshold that is less than the first predetermined threshold in response to the autostart of the engine. Vehicle system after Claim 7 wherein the controller is further programmed to initiate an autostart of the engine in response to an increase in the angular error - a difference between the steering wheel angle and the drive angle before an autostop and the steering wheel angle and the drive angle after an autostop of the engine - an angular error threshold exceed. Vehicle system after Claim 8 wherein the controller is further programmed to drive the electrical actuator to reduce the angular error. Vehicle system after Claim 9 wherein the controller is further programmed to command electric actuator to adjust an angular position of one or more wheels. Vehicle system after Claim 9 wherein the controller is further programmed to command the electrical actuator to adjust an angular position of a steering wheel mechanism. Vehicle comprising: a motor configured to automatically stop and automatically start; and a controller programmed to drive an electric actuator coupled to a steering mechanism to synchronize a drive angle of the vehicle and a steering wheel angle of the vehicle in response to a parameter indicative of a probability of a wheel slip event exceeds a threshold and that the steering wheel angle is greater than a predetermined threshold. Vehicle after Claim 12 wherein the controller is further programmed to drive the electrical actuator in response to the temperature measured outside the vehicle being less than a temperature threshold. Vehicle after Claim 12 wherein the controller is further programmed to drive the electrical actuator in response to a precipitation sensor sending a signal indicative of the presence of precipitate. Vehicle after Claim 12 wherein the controller is further programmed to drive the electric actuator in response to a wheel speed difference between at least two of the wheels exceeding a wheel speed error threshold.

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